support rescheduling/resetting timers when the time source changes

lib/zm/reactor.rb

@@ -3,25 +3,25 @@
 # Author:: Chuck Remes
 # Homepage::  http://github.com/chuckremes/zmqmachine
 # Date:: 20100602
-# 
+#
 #----------------------------------------------------------------------------
 #
 # Copyright (C) 2010 by Chuck Remes. All Rights Reserved.
 # Email: cremes at mac dot com
-# 
+#
 # (The MIT License)
-# 
+#
 # Permission is hereby granted, free of charge, to any person obtaining
 # a copy of this software and associated documentation files (the
 # 'Software'), to deal in the Software without restriction, including
 # without limitation the rights to use, copy, modify, merge, publish,
 # distribute, sublicense, and/or sell copies of the Software, and to
 # permit persons to whom the Software is furnished to do so, subject to
 # the following conditions:
-# 
+#
 # The above copyright notice and this permission notice shall be
 # included in all copies or substantial portions of the Software.
-# 
+#
 # THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
 # EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
@@ -32,13 +32,13 @@
 #
 #---------------------------------------------------------------------------
 #
-# 
+#
 
 module ZMQMachine
 
   class Reactor
     attr_reader :name
-    
+
     # +poll_interval+ is the number of milliseconds to block while
     # waiting for new 0mq socket events; default is 0
     #
@@ -61,7 +61,7 @@ def initialize name, poll_interval = 0
     end
 
     # Returns true when the reactor is running OR while it is in the
-    # midst of a shutdown request. 
+    # midst of a shutdown request.
     #
     # Returns false when the reactor thread does not exist.
     #
@@ -124,12 +124,12 @@ def join delay = nil
         end
       end
     end
-    
+
     # Kills the running reactor instance by terminating its thread.
     #
     # After the thread exits, the reactor attempts to clean up after itself
     # and kill any pending I/O.
-    # 
+    #
     def kill
       @stopping = true
       @thread.kill
@@ -273,7 +273,7 @@ def sub_socket handler_instance
       save_socket sock
       sock
     end
-    
+
     # Registers the +sock+ for POLLOUT events that will cause the
     # reactor to call the handler's on_writable method.
     #
@@ -332,6 +332,15 @@ def periodical_timer delay, timer_proc = nil, &blk
     def cancel_timer timer
       @timers.cancel timer
     end
+
+    # Asks all timers to reschedule themselves starting from Timers.now.
+    # Typically called when the underlying time source for the ZM::Timers
+    # class has been replaced; existing timers may not fire as expected, so
+    # we ask them to reset themselves.
+    #
+    def reschedule_timers
+      @timers.reschedule
+    end
 
 
     private

lib/zm/timers.rb

@@ -122,6 +122,19 @@ def fire_expired
       save.each { |timer| @timers.add timer }
     end
 
+    # Runs through all timers and asks each one to reschedule itself
+    # from Timers.now + whatever delay was originally recorded.
+    #
+    def reschedule
+      timers = @timers.dup
+      @timers.clear
+
+      timers.each do |timer|
+        timer.reschedule
+        @timers.add timer
+      end
+    end
+
     # Returns the current time using the following algo:
     #
     #  (Time.now.to_f * 1000).to_i
@@ -158,6 +171,7 @@ class Timer
     attr_reader :fire_time
 
     # +time+ is in milliseconds
+    #
     def initialize timers, delay, periodical, timer_proc = nil, &blk
       @timers = timers
       @delay = delay.to_i
@@ -178,6 +192,8 @@ def fire
       schedule_firing_time if @periodical
     end
 
+    # Cancels this timer from firing.
+    #
     def cancel
       @timers.cancel self
     end
@@ -186,14 +202,22 @@ def <=>(other)
       self.fire_time <=> other.fire_time
     end
 
+    # True when the timer should be fired; false otherwise.
+    #
     def expired? time
       time ||= now
       time > @fire_time
     end
 
+    # True when this is a periodical timer; false otherwise.
+    #
     def periodical?
       @periodical
     end
+
+    def reschedule
+      schedule_firing_time
+    end
 
 
     private
@@ -209,12 +233,11 @@ def periodical?
     # next timer to fire at, 17 + delay 5 = 22
     # had it not been late, it would fire at 20
     def schedule_firing_time
-      @fire_time = now + @delay
+      @initiated = Timers.now
+
+      @fire_time = @initiated + @delay
     end
 
-    def now
-      Timers.now
-    end
   end # class Timer
 
 end # module ZMQMachine